Identification of mRNA for PDGF B-chain in human megakaryocytes isolated using a novel immunomagnetic separation method.

A rapid and simple method has been developed for the separation of pure populations of intact human megakaryocytes from whole bone marrow. Megakaryocytes were specifically recognized using monoclonal antibodies coupled to magnetizable articles. Cells labelled with the magnetizable probe were separated from unlabelled cells by introduction of a magnetic field. The technique yields megakaryocyte suspensions with a purity of greater than 98%. Electron microscope examination showed that the ultrastructure of the isolated megakaryocytes was well preserved. Using this method of cell purification, we have investigated expression of the gene for platelet-derived growth factor (PDGF). RNA was isolated from cells harvested from either ribs or posterior iliac crest. The RNA was spotted onto nitrocellulose, and then hybridized using a c-sis riboprobe specific for PDGF B chain mRNA. We demonstrate that mRNA for PDGF B-chain is identifiable in samples of 50,000 cells. We conclude that PDGF is synthesized by the megakaryocyte.